An inverter integrated electric compressor including an inverter apparatus integrally incorporated therein is known as a compressor for an air-conditioning apparatus mounted in a hybrid car, an electric car, and the like. In the inverter integrated electric compressor, an inverter accommodating part (inverter box) is provided in the outer periphery of a housing in which an electric motor and a compression mechanism are built, and the inverter apparatus is incorporated in the inverter accommodating part. The inverter apparatus converts DC power supplied from a power supply into AC power, and applies the AC power to the electric motor through a glass sealed terminal.
The inverter apparatus generally includes: a power system circuit board on which a switching circuit including a plurality of semiconductor switching elements, such as insulated gate bipolar transistors (IGBTs), is mounted, the semiconductor switching elements converting DC power into AC power; and a control circuit board on which a control communication circuit including elements that operate at a low voltage, such as a CPU, is mounted. The two circuit boards are placed one above the other at two stages, and are accommodated and set in an inverter case or an outer frame part, to be thereby integrally incorporated in an outer peripheral part of a compressor housing.
In the inverter integrated electric compressor described above, a high voltage system and a low voltage system are mixedly provided in the inverter apparatus, and hence it is necessary to block electromagnetic noise to thereby improve the stability of the control circuit. At the same time, the inverter integrated electric compressor described above is used under severe temperature conditions and vibration conditions, and hence the inverter apparatus is also required to have high vibration-proof properties, moisture-proof properties, and electrical insulating properties. Consequently, it is proposed that an inverter accommodating part in which an inverter apparatus is incorporated is filled with a resin gel material and that a control circuit board is set in a floating state in the resin gel material, and it is also proposed that a shield plate is provided between a low voltage control circuit board and a high voltage circuit for motor driving, the space between which is filled with a resin gel material (see, for example, PTL 1 and PTL 2).